Field of the Invention
The present invention relates to a sheet stacking apparatus on which sheets are stacked and an image forming apparatus provided with the sheet stacking apparatus.
Description of the Related Art
An image forming apparatus forms an image by an image forming unit on a sheet fed from a sheet feed cassette or a manual feed tray. The sheet with the image formed thereon is discharged outside the apparatus by an ejection roller. The sheet discharged outside the apparatus is stacked on a discharge tray.
An image forming apparatus typically has a door to allow access to a conveyance path or a maintenance section for jam clearance and maintenance. The door is opened and closed relative to an apparatus main body about a shaft provided at a lower portion of the apparatus main body.
The door may be provided with a discharge tray (Japanese Patent Laid-Open No. 9-190029 and No. 2010-8967), or a manual feed tray (Japanese Patent Laid-Open No. 2006-341987). In these configurations, the sheets stacked on the discharge tray or the manual feed tray may fall at the time at which the door is opened. Then, in Japanese Patent Laid-Open No. 9-190029, an angle of the discharge tray is adjusted by a link at the time of opening and closing of the door to prevent the sheets from falling. In Japanese Patent Laid-Open No. 2006-341987, a fall prevention claw is provided at an end of the manual feed tray. Ends of the stacked sheets are made to abut against the claw for the fall prevention.
The configuration in which the angle of the discharge tray is adjusted by the link at the time of opening and closing of the door as in Japanese Patent Laid-Open No. 9-190029 becomes complicated.
The configuration in which the fall prevention claw for the sheets is provided in the tray as in Japanese Patent Laid-Open No. 2006-341987 has the following problem: if the door is opened quickly, the sheet may move quickly until being dammed up by the fall prevention claw and may cross over the fall prevention claw, whereby falling of the sheet cannot be prevented. If a distance from the center of the shaft of the door to the tray is long, the tray provided in the door moves quickly at the time at which the door is opened, and the sheet stacked on the tray falls more easily.